Cephalosporins having a ureido acyl side chain are disclosed in U.S. Pat. No. 3,673,183; 3,708,479; 3,833,568; and 3,860,591. Cephalosporins having various acyl side chains and a 7.alpha.-methoxy substituent are taught in various patents including U.S. Pat. Nos. 3,775,410; 3,780,031; 3,780,033; 3,780,034; 3,780,037; 3,843,641; etc.
Cephalosporins having an acylureido acyl side chain are disclosed in U.S. Pat. Nos. 3,687,949 and 3,925,368 and German Offenlegungsschrift Nos. 2,513,954 and 2,514,019.